Brake pedal feel issue - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Open Loop · 01-01-2020, 08:39 AM

Hi everyone. My 2013 FR-S with 60k miles (solo spec coupe autocross/time trials car) is exhibiting an unexpected issue with brake pedal feel. First application of the pedal while driving seems to have a bit more travel than the second application immediately thereafter. My initial thought is brake master cylinder, but I can't feel any sinking of the pedal with constant pressure on it. This issue seems to have arisen after the racing season ended and when the car gets parked for a week or so without being driven, left outside but under a carport. No apparent buildup of rust on the rotors. I am interested in whether anyone has experienced this before. Thank you.

skylinekin · 01-01-2020, 09:40 AM

When was the last brake fluid change\bleed?

Open Loop · 01-01-2020, 10:32 AM

Quote:

Originally Posted by skylinekin

When was the last brake fluid change\bleed?

Middle of last season Stoptech 660.

soundman98 · 01-01-2020, 11:59 AM

i would agree with your diagnosis given the pedal feel, however i would try flushing the lines first to be hopeful for some air in one of the lines before going through the ordeal of changing the brake booster.

skylinekin · 01-01-2020, 12:42 PM

How worn are the front and rear brake pads?

Open Loop · 01-02-2020, 06:40 AM

Quote:

Originally Posted by soundman98

i would agree with your diagnosis given the pedal feel, however i would try flushing the lines first to be hopeful for some air in one of the lines before going through the ordeal of changing the brake booster.

Shouldn't I just replace the master cylinder and leave the booster in the car? I don't think it's exhibiting any symptoms of a bad booster.

Quote:

Originally Posted by skylinekin

How worn are the front and rear brake pads?

They're OK. Half worn at most.

Gazzabean · 01-03-2020, 03:38 AM

Buy a brake fluid moisture tester from amazon for £5. Place into reservoir, if it flashes orange to red, you need to change it out. What you’re experiencing is similar to me. What is happening is the heat from braking is actually boiling the “water” inside the brake fluid. Causing the brake line to expand. If you leave the brake fluid in there, it will corrode your brake lines, soften your pedal dramatically and therefore decrease stopping power. I have racing fluid and SS braided lines with stock callipers, EBC Grooved and EBC yellowstuff pads. You may not need the racing fluid as it is extremely expensive for a complete change, but I wouldn’t advise buying DOT 3/4/5.1. Somewhere in between. If you’re not sure how to bleed the system in the correct order and what steps to take, or any questions at all, PM me.

Hope this helps!!!

01-01-2020, 08:39 AM	#1
Open Loop 2013 FR-S Whiteout / SSC Join Date: Aug 2016 Drives: 2013 FR-S Location: Pennsylvania Posts: 107 Thanks: 59 Thanked 43 Times in 26 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	Brake pedal feel issue Hi everyone. My 2013 FR-S with 60k miles (solo spec coupe autocross/time trials car) is exhibiting an unexpected issue with brake pedal feel. First application of the pedal while driving seems to have a bit more travel than the second application immediately thereafter. My initial thought is brake master cylinder, but I can't feel any sinking of the pedal with constant pressure on it. This issue seems to have arisen after the racing season ended and when the car gets parked for a week or so without being driven, left outside but under a carport. No apparent buildup of rust on the rotors. I am interested in whether anyone has experienced this before. Thank you.

01-01-2020, 11:59 AM	#4
soundman98 ProCrastinationConsultant Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 11,330 Thanks: 35,240 Thanked 13,673 Times in 6,781 Posts Mentioned: 98 Post(s) Tagged: 0 Thread(s)	i would agree with your diagnosis given the pedal feel, however i would try flushing the lines first to be hopeful for some air in one of the lines before going through the ordeal of changing the brake booster. __________________ "The time you enjoy wasting is not wasted time"

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Brake firmness/pedal feel	Hyper4mance2k	Suspension \| Chassis \| Brakes -- Sponsored by 949 Racing	40	05-22-2019 12:22 PM
Clutch pedal/transmission issue	ft86chiver	Issues \| Warranty \| Recalls / TSB	3	06-27-2016 04:19 PM
How to fix light feel with the clutch pedal?	hot86lova	Scion FR-S / Toyota 86 GT86 General Forum	8	08-04-2014 01:06 AM
Disappointed brake pedal feel, what am I doing wrong	ZionsWrath	Other Vehicles & General Automotive Discussions	12	11-15-2013 02:03 PM
Odd brake pedal feel, fade?	yomny	Suspension \| Chassis \| Brakes -- Sponsored by 949 Racing	28	09-11-2012 12:29 PM

01-01-2020, 09:40 AM	#2
skylinekin Senior Member Join Date: Jul 2013 Drives: 22 GR86, 13 FRS, 15 BRZ, 13 FRS Location: SE Michigan Posts: 368 Thanks: 44 Thanked 70 Times in 48 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	When was the last brake fluid change\bleed?

01-01-2020, 12:42 PM	#5
skylinekin Senior Member Join Date: Jul 2013 Drives: 22 GR86, 13 FRS, 15 BRZ, 13 FRS Location: SE Michigan Posts: 368 Thanks: 44 Thanked 70 Times in 48 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	How worn are the front and rear brake pads?

01-03-2020, 03:38 AM	#7
Gazzabean Junior Member Join Date: Jan 2020 Drives: Toyota GT86 Location: North West England Posts: 8 Thanks: 0 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Buy a brake fluid moisture tester from amazon for £5. Place into reservoir, if it flashes orange to red, you need to change it out. What you’re experiencing is similar to me. What is happening is the heat from braking is actually boiling the “water” inside the brake fluid. Causing the brake line to expand. If you leave the brake fluid in there, it will corrode your brake lines, soften your pedal dramatically and therefore decrease stopping power. I have racing fluid and SS braided lines with stock callipers, EBC Grooved and EBC yellowstuff pads. You may not need the racing fluid as it is extremely expensive for a complete change, but I wouldn’t advise buying DOT 3/4/5.1. Somewhere in between. If you’re not sure how to bleed the system in the correct order and what steps to take, or any questions at all, PM me. Hope this helps!!!

User Name		Remember Me?
Password